1 /*******************************************************************************
2  *
3  * Module Name: nsnames - Name manipulation and search
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2012, Intel Corp.
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions, and the following disclaimer,
16  *    without modification.
17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18  *    substantially similar to the "NO WARRANTY" disclaimer below
19  *    ("Disclaimer") and any redistribution must be conditioned upon
20  *    including a substantially similar Disclaimer requirement for further
21  *    binary redistribution.
22  * 3. Neither the names of the above-listed copyright holders nor the names
23  *    of any contributors may be used to endorse or promote products derived
24  *    from this software without specific prior written permission.
25  *
26  * Alternatively, this software may be distributed under the terms of the
27  * GNU General Public License ("GPL") version 2 as published by the Free
28  * Software Foundation.
29  *
30  * NO WARRANTY
31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41  * POSSIBILITY OF SUCH DAMAGES.
42  */
43 
44 #include <acpi/acpi.h>
45 #include "accommon.h"
46 #include "amlcode.h"
47 #include "acnamesp.h"
48 
49 #define _COMPONENT          ACPI_NAMESPACE
50 ACPI_MODULE_NAME("nsnames")
51 
52 /*******************************************************************************
53  *
54  * FUNCTION:    acpi_ns_build_external_path
55  *
56  * PARAMETERS:  Node            - NS node whose pathname is needed
57  *              Size            - Size of the pathname
58  *              *name_buffer    - Where to return the pathname
59  *
60  * RETURN:      Status
61  *              Places the pathname into the name_buffer, in external format
62  *              (name segments separated by path separators)
63  *
64  * DESCRIPTION: Generate a full pathaname
65  *
66  ******************************************************************************/
67 acpi_status
acpi_ns_build_external_path(struct acpi_namespace_node * node,acpi_size size,char * name_buffer)68 acpi_ns_build_external_path(struct acpi_namespace_node *node,
69 			    acpi_size size, char *name_buffer)
70 {
71 	acpi_size index;
72 	struct acpi_namespace_node *parent_node;
73 
74 	ACPI_FUNCTION_ENTRY();
75 
76 	/* Special case for root */
77 
78 	index = size - 1;
79 	if (index < ACPI_NAME_SIZE) {
80 		name_buffer[0] = AML_ROOT_PREFIX;
81 		name_buffer[1] = 0;
82 		return (AE_OK);
83 	}
84 
85 	/* Store terminator byte, then build name backwards */
86 
87 	parent_node = node;
88 	name_buffer[index] = 0;
89 
90 	while ((index > ACPI_NAME_SIZE) && (parent_node != acpi_gbl_root_node)) {
91 		index -= ACPI_NAME_SIZE;
92 
93 		/* Put the name into the buffer */
94 
95 		ACPI_MOVE_32_TO_32((name_buffer + index), &parent_node->name);
96 		parent_node = parent_node->parent;
97 
98 		/* Prefix name with the path separator */
99 
100 		index--;
101 		name_buffer[index] = ACPI_PATH_SEPARATOR;
102 	}
103 
104 	/* Overwrite final separator with the root prefix character */
105 
106 	name_buffer[index] = AML_ROOT_PREFIX;
107 
108 	if (index != 0) {
109 		ACPI_ERROR((AE_INFO,
110 			    "Could not construct external pathname; index=%u, size=%u, Path=%s",
111 			    (u32) index, (u32) size, &name_buffer[size]));
112 
113 		return (AE_BAD_PARAMETER);
114 	}
115 
116 	return (AE_OK);
117 }
118 
119 /*******************************************************************************
120  *
121  * FUNCTION:    acpi_ns_get_external_pathname
122  *
123  * PARAMETERS:  Node            - Namespace node whose pathname is needed
124  *
125  * RETURN:      Pointer to storage containing the fully qualified name of
126  *              the node, In external format (name segments separated by path
127  *              separators.)
128  *
129  * DESCRIPTION: Used for debug printing in acpi_ns_search_table().
130  *
131  ******************************************************************************/
132 
acpi_ns_get_external_pathname(struct acpi_namespace_node * node)133 char *acpi_ns_get_external_pathname(struct acpi_namespace_node *node)
134 {
135 	acpi_status status;
136 	char *name_buffer;
137 	acpi_size size;
138 
139 	ACPI_FUNCTION_TRACE_PTR(ns_get_external_pathname, node);
140 
141 	/* Calculate required buffer size based on depth below root */
142 
143 	size = acpi_ns_get_pathname_length(node);
144 	if (!size) {
145 		return_PTR(NULL);
146 	}
147 
148 	/* Allocate a buffer to be returned to caller */
149 
150 	name_buffer = ACPI_ALLOCATE_ZEROED(size);
151 	if (!name_buffer) {
152 		ACPI_ERROR((AE_INFO, "Could not allocate %u bytes", (u32)size));
153 		return_PTR(NULL);
154 	}
155 
156 	/* Build the path in the allocated buffer */
157 
158 	status = acpi_ns_build_external_path(node, size, name_buffer);
159 	if (ACPI_FAILURE(status)) {
160 		ACPI_FREE(name_buffer);
161 		return_PTR(NULL);
162 	}
163 
164 	return_PTR(name_buffer);
165 }
166 
167 /*******************************************************************************
168  *
169  * FUNCTION:    acpi_ns_get_pathname_length
170  *
171  * PARAMETERS:  Node        - Namespace node
172  *
173  * RETURN:      Length of path, including prefix
174  *
175  * DESCRIPTION: Get the length of the pathname string for this node
176  *
177  ******************************************************************************/
178 
acpi_ns_get_pathname_length(struct acpi_namespace_node * node)179 acpi_size acpi_ns_get_pathname_length(struct acpi_namespace_node *node)
180 {
181 	acpi_size size;
182 	struct acpi_namespace_node *next_node;
183 
184 	ACPI_FUNCTION_ENTRY();
185 
186 	/*
187 	 * Compute length of pathname as 5 * number of name segments.
188 	 * Go back up the parent tree to the root
189 	 */
190 	size = 0;
191 	next_node = node;
192 
193 	while (next_node && (next_node != acpi_gbl_root_node)) {
194 		if (ACPI_GET_DESCRIPTOR_TYPE(next_node) != ACPI_DESC_TYPE_NAMED) {
195 			ACPI_ERROR((AE_INFO,
196 				    "Invalid Namespace Node (%p) while traversing namespace",
197 				    next_node));
198 			return 0;
199 		}
200 		size += ACPI_PATH_SEGMENT_LENGTH;
201 		next_node = next_node->parent;
202 	}
203 
204 	if (!size) {
205 		size = 1;	/* Root node case */
206 	}
207 
208 	return (size + 1);	/* +1 for null string terminator */
209 }
210 
211 /*******************************************************************************
212  *
213  * FUNCTION:    acpi_ns_handle_to_pathname
214  *
215  * PARAMETERS:  target_handle           - Handle of named object whose name is
216  *                                        to be found
217  *              Buffer                  - Where the pathname is returned
218  *
219  * RETURN:      Status, Buffer is filled with pathname if status is AE_OK
220  *
221  * DESCRIPTION: Build and return a full namespace pathname
222  *
223  ******************************************************************************/
224 
225 acpi_status
acpi_ns_handle_to_pathname(acpi_handle target_handle,struct acpi_buffer * buffer)226 acpi_ns_handle_to_pathname(acpi_handle target_handle,
227 			   struct acpi_buffer * buffer)
228 {
229 	acpi_status status;
230 	struct acpi_namespace_node *node;
231 	acpi_size required_size;
232 
233 	ACPI_FUNCTION_TRACE_PTR(ns_handle_to_pathname, target_handle);
234 
235 	node = acpi_ns_validate_handle(target_handle);
236 	if (!node) {
237 		return_ACPI_STATUS(AE_BAD_PARAMETER);
238 	}
239 
240 	/* Determine size required for the caller buffer */
241 
242 	required_size = acpi_ns_get_pathname_length(node);
243 	if (!required_size) {
244 		return_ACPI_STATUS(AE_BAD_PARAMETER);
245 	}
246 
247 	/* Validate/Allocate/Clear caller buffer */
248 
249 	status = acpi_ut_initialize_buffer(buffer, required_size);
250 	if (ACPI_FAILURE(status)) {
251 		return_ACPI_STATUS(status);
252 	}
253 
254 	/* Build the path in the caller buffer */
255 
256 	status =
257 	    acpi_ns_build_external_path(node, required_size, buffer->pointer);
258 	if (ACPI_FAILURE(status)) {
259 		return_ACPI_STATUS(status);
260 	}
261 
262 	ACPI_DEBUG_PRINT((ACPI_DB_EXEC, "%s [%X]\n",
263 			  (char *)buffer->pointer, (u32) required_size));
264 	return_ACPI_STATUS(AE_OK);
265 }
266